How do you bleed hot water heat pipe line?

Air in the system will sound like a river flowing through your home. Fixing it is easy if you know how.

Hot water heating systems must be free of air to operate properly. The art of purging air from one of these systems comes with experience. There are usually purge setups in the piping, if the system was installed properly.

The purge setup will consist of one ball valve or gate valve and one boiler drain somewhere in the loop or zone.

There should be a half inch copper line connected to the water in the house that's used to fill the boiler and to purge air. This line will have an auto feeder valve somewhere between the tie into the water lines and the boiler.

There is a lever on top of the auto feed valve. This lever is to override the automatic setting that keeps the boiler at the right pressure. When lifted up the lever allows city water pressure to be fed into the boiler.

When the lever is down the setting will be somewhere between 12 and 25 pounds. This safeguards the system in case of a leak somewhere. Water will be added automatically.

The way we purge the system is by hooking a hose to the boiler drain in the purge setup. Close the ball or gate valve and feed water through the system and out the boiler drain. The ball valve is to make sure the water we're putting in goes through the entire system before exiting.

After the hose is hooked up and opened and the ball valve is closed, lift the lever on the automatic feeder and force city water into the boiler, around the loop your purging and out the hose.

Be sure to watch the pressure gauge on the boiler and never exceed twenty five pounds. You will set off the pressure relief valve at 30 pounds. This is why the hose must be opened before the lever is lifted on the auto feeder.

Put the hose end into a five gallon bucket and watch for air bubbles. Once the air bubbles have subsided, allow the system to purge for a few more minutes.

Close the lever on the auto feeder and then the boiler drain. Open the ball valve and you're done.